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  <title>ol-ext: AnimatedCluster</title>
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  <meta name="description" content="A cluster layer for OpenLayers (ol) that animates clusters on zoom change." />
  <meta name="keywords" content="ol3,cluster,animation,layer,selectio,animate,animated clusters,openlayers" />

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  <a href="https://github.com/Viglino/ol-ext" class="icss-github-corner"><i></i></a>
  
  <a href="../../index.html">
    <h1>ol-ext: AnimatedCluster</h1>
  </a>
  <p class="info">
    <i>ol.layer.AnimatedCluster</i> is a layer that animates clusters on zoom change. 
    The layer is created with an ol.source.Cluster as standard cluster vector layers.
    <br/>
    <i>ol.interaction.SelectCluster</i> is a select interaction.
    On select cluster springs apart to reveal the features.
    The revealed features are themselves selectable.
    Revealed features are themselves a cluster with an attribute 'features' that contain the original feature. 
    <br/>
    The example uses the convex envelope calculation to draw a polygon around the points of the cluster 
    (see <a href="../geom/map.cluster.convexhull.html">ol-ext convex hull example</a>).
  </p>

  <!-- DIV pour la carte -->
  <div id="map" style="width:600px; height:400px;"></div>

  <div class="options">
    <h2>Cluster options:</h2>
    <input id="animatecluster" type="checkbox" checked="checked" onchange="clusterLayer.set('animationDuration',(this.checked ? 700:0));" />
    <label for="animatecluster">animate cluster</label>
    <br />
    Number of features:
    <br/>
    <input type="number" value="2000" onchange="addFeatures(this.value);" />
    <h2>Select options:</h2>
    <input id="animatesel" type="checkbox" checked="checked" onchange="selectCluster.animate = this.checked" />
    <label for="animatesel">animate selection</label>
    <br />
    <input id="haslink" type="checkbox" checked="checked" onchange="selectCluster.clear();" />
    <label for="haslink">show links on select</label>
    <h2>Style:</h2>
    <input id="convexhull" type="checkbox" onchange="selectCluster.clear();" />
    <label for="convexhull">display convex envelope</label>
  </div>
  <div class="infos"></div>

  <script type="text/javascript">
    // Layers
    var layers = [ new ol.layer.Tile({
      source: new ol.source.OSM()
    })];

    // The map
    var map=new ol.Map({
      target: 'map',
      view: new ol.View({
        zoom: 4,
        center: [166326, 5992663]
      }),
      layers: layers
    });

    // Addfeatures to the cluster
    function addFeatures(nb){
      var ext = map.getView().calculateExtent(map.getSize());
      var features=[];
      for (var i=0; i<nb; ++i){
        features[i]=new ol.Feature(new ol.geom.Point([ext[0]+(ext[2]-ext[0])*Math.random(), ext[1]+(ext[3]-ext[1])*Math.random()]));
        features[i].set('id',i);
      }
      clusterSource.getSource().clear();
      clusterSource.getSource().addFeatures(features);
    }

    // Style for the clusters
    var styleCache = {};
    function getStyle (feature, resolution){
      var size = feature.get('features').length;
      var style = styleCache[size];
      if (!style) {
        var color = size>25 ? "192,0,0" : size>8 ? "255,128,0" : "0,128,0";
        var radius = Math.max(8, Math.min(size*0.75, 20));
        var dash = 2*Math.PI*radius/6;
        var dash = [ 0, dash, dash, dash, dash, dash, dash ];
        style = styleCache[size] = new ol.style.Style({
          image: new ol.style.Circle({
            radius: radius,
            stroke: new ol.style.Stroke({
              color: "rgba("+color+",0.5)", 
              width: 15 ,
              lineDash: dash,
              lineCap: "butt"
            }),
            fill: new ol.style.Fill({
              color:"rgba("+color+",1)"
            })
          }),
          text: new ol.style.Text({
            text: size.toString(),
            //font: 'bold 12px comic sans ms',
            //textBaseline: 'top',
            fill: new ol.style.Fill({
              color: '#fff'
            })
          })
        });
      }
      return style;
    }

    // Cluster Source
    var clusterSource=new ol.source.Cluster({
      distance: 40,
      source: new ol.source.Vector()
    });
    // Animated cluster layer
    var clusterLayer = new ol.layer.AnimatedCluster({
      name: 'Cluster',
      source: clusterSource,
      animationDuration: $("#animatecluster").prop('checked') ? 700:0,
      // Cluster style
      style: getStyle
    });
    map.addLayer(clusterLayer);
    // add 2000 features
    addFeatures(2000);

    // Style for selection
    var img = new ol.style.Circle({
      radius: 5,
      stroke: new ol.style.Stroke({
        color:"rgba(0,255,255,1)", 
        width:1 
      }),
      fill: new ol.style.Fill({
        color:"rgba(0,255,255,0.3)"
      })
    });
    var style0 = new ol.style.Style({
      image: img
    });
    var style1 = new ol.style.Style({
      image: img,
      // Draw a link beetween points (or not)
      stroke: new ol.style.Stroke({
        color:"#fff", 
        width:1 
      }) 
    });
    // Select interaction to spread cluster out and select features
    var selectCluster = new ol.interaction.SelectCluster({
      // Point radius: to calculate distance between the features
      pointRadius:7,
      // circleMaxObjects: 40,
      // spiral: false,
      // autoClose: false,
      // toggleCondition: ol.events.condition.singleClick,
      animate: $("#animatesel").prop('checked'),
      // Feature style when it springs apart
      featureStyle: function(){
        return [ $("#haslink").prop('checked') ? style1:style0 ]
      },
      // selectCluster: false,	// disable cluster selection
      // Style to draw cluster when selected
      style: function(f,res){
        var cluster = f.get('features');
        if (cluster.length>1){
          var s = [ getStyle(f,res) ];
          if ($("#convexhull").prop("checked") && ol.coordinate.convexHull){
            var coords = [];
            for (i=0; i<cluster.length; i++) coords.push(cluster[i].getGeometry().getFirstCoordinate());
            var chull = ol.coordinate.convexHull(coords);
            s.push ( new ol.style.Style({
              stroke: new ol.style.Stroke({ color: "rgba(0,0,192,0.5)", width:2 }),
              fill: new ol.style.Fill({ color: "rgba(0,0,192,0.3)" }),
              geometry: new ol.geom.Polygon([chull]),
              zIndex: 1
            }));
          }
          return s;
        } else {
          return [
          new ol.style.Style({
            image: new ol.style.Circle ({
              stroke: new ol.style.Stroke({ color: "rgba(0,0,192,0.5)", width:2 }),
              fill: new ol.style.Fill({ color: "rgba(0,0,192,0.3)" }),
              radius:5
            })
          })];
        }
      }
    });
    map.addInteraction(selectCluster);

    // On selected => get feature in cluster and show info
    selectCluster.getFeatures().on(['add'], function (e){
      var c = e.element.get('features');
      if (c.length==1){
        var feature = c[0];
        $(".infos").html("One feature selected...<br/>(id="+feature.get('id')+")");
      } else {
        $(".infos").text("Cluster ("+c.length+" features)");
      }
    })
    selectCluster.getFeatures().on(['remove'], function (e){
      $(".infos").html("");
    })

  </script>

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